Scholars Say Causes of Stuttering Are Multiple and Interconnected
Studies are exploring why some children outgrow the problem
When the Academy Awards ceremony aired on Sunday, Texas speech therapist Lana Dodgen was rooting for “The King’s Speech,” up for a dozen Oscars for its depiction of British King George VI’s struggle with stuttering.
Ms. Dodgen, who runs the Mesquite Independent School District’s chapter of the National Stuttering Association’s children’s-support group, said she and other advocates hope the film will bring awareness to stuttering the way “Rain Man” did to autism. The movie has already drawn broad interest to the disorder, which affects about 5 percent of preschoolers at some point in their language development and leaves 1 percent, or more than 3 million Americans, permanently struggling to speak.
Yet new findings discussed at a Feb. 20 research symposium on stuttering, held in Washington during the annual conference of the American Association for the Advancement of Science, suggest educators are just beginning to understand the interconnected causes of the condition.
Anne Smith, the director of Purdue University’s Speech Neurophysiology Lab, in West Lafayette, Ind., said researchers no longer think the root of stuttering lies in any one problem.
“The causal factors are many: linguistic factors, cognitive factors, psychosocial factors, and genetic factors,” she said during the symposium. “It’s emergent; there are a number of underlying factors, and it’s the way they interact that produces stuttering.”
Mismatch in the Brain
It’s common for a stutterer’s speech to become more unstable as sentences become more complex. In a study published in the journal NeuroImage in November, Luc F. de Nil, a professor of speech-language pathology at the University of Toronto, found that when someone stutters, even purposely, it overactivates and mistimes parts of the cerebellum associated with integrating sense perception with body movements, which may contribute to a mismatch between thinking a phrase and speaking it.
All children learn language a bit like the way they learn to ride a bike, wobbly at first and becoming smoother with practice. According to a series of 2010 studies co-written by Ms. Smith—part of 20 years of ongoing research on adult and child stutterers underwritten by the National Institutes of Health—about 60 percent of preschool children had normal variations in their ability to clap in time with a rhythm and in both their jaw movements and sounds when they repeated a sentence like “Buy Bobby a puppy” 10 times.
Speech consistency doesn’t come until puberty, yet even when speaking clearly, young children and adults who stutter vary more widely in their physical and voice movements than nonstutterers.
“Stuttering isn’t just these behaviors you see,” Ms. Smith said. “It’s a symptom in young children of a profound difference in the way the brain is developing.”
That difference may in part be genetic, suggests research by Dennis T. Drayna, a section chief for the Laboratory of Molecular Genetics at the National Institute on Deafness and Other Communication Disorders, in Bethesda, Md.
Building on prior studies of identical twins, Mr. Drayna’s team found in studies of families last year that stuttering is highly heritable.
At least three different genes have been associated with increased stuttering. Mr. Drayna is now experimenting with mice that have been injected with the faulty gene to determine if they have changes in their own vocalizations that could help pinpoint the cause.
Outgrowing the Disorder
Ms. Smith said half of those who stutter at the start of school will have stopped within a few years. Her team has identified 72 4- and 5-year-olds who stutter, along with 45 peers who do not, and will run each through a two-day battery of language tests once a year for five years to track differences between children who continue to stutter and those who become fluent on their own or with speech therapy.
Braden Barber, 17, is among the 1 percent whose stuttering has persisted. Diagnosed at age 2, he went through several speech pathologists in elementary and middle school, but he said he stopped seeing the last one a year ago and hasn’t used many of the anti-stuttering strategies, “because most of them don’t really work for me.”
“I’m not really looking for a cure for stuttering,” he said. “I try to control it as much as I can. …. I try to talk very slowly so I can keep up with my words and know what I’m going to say.”
In the process, Mr. Barber, now a junior at The Colony High School in The Colony, Texas, said he’s stopped following research on stuttering and started just getting more involved in the community. He has joined the Dallas-area Teens Who Stutter group, and developed an informational letter for students who stutter to give to their teachers, describing the disorder and ways the teacher can support the student in class by encouraging him or her to speak without applying pressure.
His advice echoes that of many researchers and advocates for stuttering students.
“The biggest mistake is telling the child, ‘Just slow down, take your time, and you’ll get it out,’” said Tommie L. Robinson Jr., the director of the Scottish Rite Center for Childhood Language Disorders in the Children’s Hearing and Speech Center at Children’s National Medical Center in Washington. He is the immediate past president of the American Speech-Language-Hearing Association.
“If teachers model fluid, easy talking, that’s far more powerful,” Mr. Robinson said.
Keith Adams, the principal at West Mesquite High School in Texas and a stutterer since early childhood, said he tries to reach out to students who stutter, both through the school district support group and individually.
“What we want to try to do with the district support group is to show kids it’s OK to be a stutterer,” Mr. Adams said. “It’s something you have to manage, but it’s part of you.”
Vol. 30, Issue 22, Page 6Published in Print: March 2, 2011, as Scholars Say Causes of Stuttering Are Multiple and Interconnected